Transfer files to/from memory

[jl-wynen]

When Scitacean is tightly integrated into a workflow, there may not be a need to save data to disk. Instead, it could be useful to load some data directly into memory from the fileserver or write an in-memory buffer to the fileserver.

This would require support from File which could store a BytesIO instead of a Path for local. And the file transfers would read from / write to the buffer instead of a actual file.

There are some downsides:

• For downloads, the data wouldn't be cached on the local machine. So it would have to be downloaded again if the program needs to run again.
• For uploads, if the upload fails, the data may be lost if the program can't recover automatically (or through user input in an interactive session).

[bpedersen2]

Interessting feature, especially for small datafiles in automated workflows.

I would suggest to make an (not too high) upper bound on the filesize where this is possible, as nowadays datafiles in the TB-range are not uncommon.